Observations

Description

Valves are elliptic. Raphe valve has a narrow linear axial area and transversely rectangular, or elliptic central area. The raphe is filiform and straight with slightly expanded, almost straight or very slightly deflected external distal ends. The internal proximal raphe ends are deflected to opposite sides. The internal distal raphe ends have small helictoglossae. The rapheless valve has a narrow linear axial area and an asymmetric central area. Striae are uniseriate. Areolae are isodiametric and number 35–40 in 10 μm. The central striae have 8–9 areolae in central striae, numbering 35-40 areolae in 10 μm. The external areolae openings are very small.

Original Description

Original Description

Original Images

Cite This Page: Potapova, M. (2012). Psammothidium pennsylvanicum. In Diatoms of the United States. Retrieved March 03, 2015, from http://westerndiatoms.colorado.edu/taxa/species/psammothidium_pennsylvanicum

Valves are elliptic. The raphe valve has a narrow linear axial area and transversely rectangular, or elliptic central area. The raphe is straight. The rapheless valve has a narrow linear axial area and an asymmetric central area. Areolae number 35–40 in 10 μm within each stria.

Compare

Psammothdium pennsylvanicum differs from P. semiapertum by a higher areola density (35-40 vs 25 in P. semiapertum) within each stria.

Citations

Potapova, M. (2012).New species and combinations in monoraphid diatoms (Family Achnanthidiaceae) from North America.
Diatom Research 27(1): 29-42.doi:10.1080/0269249X.2011.644636

Links & ID's

Index Nominum Algarum (INA)

California Academy of Sciences (CAS)

North American Diatom Ecological Database (NADED)

NADED ID:

Autecology Discussion

Psammothidium pennsylvanicum has been found in 15 streams in north central Pennsylvania, including some affected by acid mine drainage. Conductivity in these streams ranged from 6 to 378 μS/cm, and pH from 4.0 to 7.0.